Locking out PDCOV requires attention to biosecurity detail

Porcine delta coronavirus (PDCOV) may not be as devastating as its relative, porcine epidemic diarrhoea virus (PEDV), but the negative impact on production is motivation enough to work to lock it out of sow farms.

Wedel has faced a couple of different episodes of the virus in sow herds. She pointed to one that surfaced last spring with an early morning call reporting 5% to 10% of gestating sows with diarrhoea and 15% that weren’t eating. “Anytime you get a call about diarrhoea in sows you think of coronaviruses,” she added.

The team quickly moved into gear to collect faecal samples and rectal swabs, wasting no time to send them in to the diagnostic laboratory. There is no vaccine for PDCOV, so upon confirmation, Iowa Select implemented a load-close-expose treatment strategy. Wedel explained that this involved lining up extra replacement gilts, closing the herd for 12 to 15 weeks and then exposing the entire herd with PDCOV.

“We’ve had very good luck with sow faeces and piglet intestines, using distilled water to dilute that and then applying an oral/nasal exposure,” she said. “You want to get immunity to the sows as quickly as possible.”

Although Iowa Select has strict biosecurity protocols in place, Wedel noted one instance of PDCOV exposure was related to remodelling and construction crews coming onto the site. Another case was traced back to a welder who came in to work on gestation stalls.

Quoting a fellow swine veterinarian, she said, “When you do a disease investigation, you’re not likely to find a smoking gun, but you might find several loaded ones lying around.” She added, “There may have been other factors involved, but you can certainly find the most likely introduction point.”

The real point, Wedel emphasised, is that it takes a very small amount of the virus to cause big problems. Iowa Select has further tightened biosecurity, including remodelling facilities and adding positive-pressure air filtration.

Her advice is to focus on biosecurity details and take the extra steps needed to do the right thing every single day.